Pretty straightforward- speaker is broken. Sound is fine if use headphones. How to fix/ whats the cause?

My guess is that the wire or ribbon connected to the speaker went wrong. Maybe broken or maybe loosen. Since the speaker is located at the top part there's a possibility that after u flip open and close the ds numerous times the ribbon cable had somehow get loose. If that is not the problem then maybe the speaker is busted. Or worst come to worst the electonic component for handling the sound speaker went haywire. Of course if want to fix u must ask the experienced one to repair it for u. I think some forummers here are able to do it.